The present invention relates to a car and track apparatus such as a sailboat traveler or the like generally comprising a roller car slideably mounted on a track.
A particular type of traveler is generally known as a roller traveler, with an example of such described in great detail in U.S. Pat. No. 4,941,197 issued to Roeser. A roller traveler is characterized in that roller bearing means are used as opposed to ball bearings. Roller bearings generally comprise substantially cylindrical members with rotational engagement occurring on their round sidewalls, and no rotational engagement on their substantially flat endwalls.
Under normal operation, cars of travelers such as that disclosed in the '197 patent do not directly contact the track, but ride on sets of lateral side bearings which engage the track along side grooves. The car ideally distributes loads evenly among its lateral bearings. Prior at travelers, including the traveler of the Roeser patent, however, have some significant problems associated with their use.
When loads are located on either side of the track, as opposed to directly along the plane normal to the track, the cars may disadvantageously distribute an uneven load. This results as loads located to one side or the other of the track tend to bear on the car in that direction, as opposed to the directly forward and rearward load placement along the length of the track in which the car is designed to run. When the load is located to one lateral side of the car, bearings along that side are exposed to increased friction and load. In severe circumstances, the car may tilt to an extent that the lower car side contacts the top of the track causing friction and scraping. These problems are most acute for traveler cars that utilize roller bearings, as opposed to ball bearings, as the roller bearings are able to work only uni-directionally.
Uneven loading on the bearings results in increased friction and decreased bearing, track, and car service life. For roller bearing cars such as that disclosed in the Roeser patent, uneven loading can also lead to the axial end wall of the roller bearing coming into moving contact with non-moving parts.
An unresolved need therefor exists for an improved traveler.